Potamogeton wrightii

Content

Description

Fruit 2-3.2 mm, with a ventral protrusion, sometimes with 1-3 dorsal keels.

Distribution

?Flores present, ?Java present, ?New Hannover present, Asia (C, E & S) to the Pacific region present, Asia-Temperate: Kazakhstan (Kazakhstan present); Korea present; Taiwan (Taiwan present), Asia-Tropical: Bangladesh (Bangladesh present); Borneo present; India present; Lesser Sunda Is. present; Maluku (Maluku present); New Guinea present; Pakistan (Pakistan present); Philippines (Philippines present); Sulawesi (Sulawesi present); Sumatera (Sumatera present); Thailand (Thailand present); Vietnam (Vietnam present), Bengal present, Far East Russia present, Halmahera present, Japan present, Kashmir present, Lombok present, Luzon present, Marianne Islands present, Minahassa present, Mindanao present, Mindoro present, Palawan present, Peninsular Malaya present, Ryukyu Islands present, Samar present

Asia (C, E & S) to the Pacific region; Kazakhstan, Far East Russia, Korea, China, Japan, Ryukyu Islands, Taiwan, Marianne Islands, Pakistan, India (Kashmir, Bengal), Bangladesh, Thailand, Vietnam; in Malesia: Sumatra (widespread), Peninsular Malaya, ?Java (fide Backer & Bakh.f.), Borneo, Philippines (Luzon, Mindoro, Palawan, Mindanao, Samar), Celebes (Minahassa), Lesser Sunda Islands (Lombok, ?Flores), Moluccas (Halmahera), New Guinea (widespread), ?New Hannover

Taxonomy

1 Potamogeton wrightii is the most frequent species of the genus in Malesia. It is highly polymorphic forming several local variants. The most aberrant ones are the following:

a) from Papua New Guinea: Leach 7805 (UPNG). It unites characters of P. wrightii, P. lucens, and P. papuanicus and may also be regarded as a hybrid or as a species in its own right;
b) from Mindoro: Britton 277 (L). A broad-leaved form with undulate margins and asymmetric leaf ground.

2. The identity of P. sumatranus Miq. is still uncertain. Various specimens of P. sumatranus were studied by Wiegleb , without reaching a final conclusion on the identity of the species. Potamogeton sumatranus is very similar to P. wrightii, but not completely identical, differing from P. wrightii by the less well developed inter-lacunar bundles, the wider leaves, and the more regular floating leaf formation. All these differentiating characters are only gradual. Potamogeton sumatranus may either prove to be a special form of P. wrightii or a product of hybridization between P. wrightii and P. nodosus. If the identity of P. wrightii and P. sumatranus can be proved, the name P. su-matranus must have priority. The form is endemic to Sumatra and occurs in lakes and ditches besides typical P. wrightii.

Citation

Chai-anan 1985 – In: Thai For. Bull.: 25

Cuming & Vidal ex A.Benn. 1892 – In: Ann. Naturhist. Hofmus. Wien: 289

Mendoza & Del Rosario 1967: Philipp. Aquat. Flow. Pl. Ferns: 41

Yang 1978 – In: Fl. Taiwan: 28

A.Benn. 1890 – In: J. Bot.: 298

A.Benn. 1914 – In: Philipp. J. Sc., Bot.: 341

Wiegleb 1990 – In: Pl. Syst. Evol.: 59

Naves 1892: Noviss. App.: 297

A.Benn. 1892 – In: Ann. Naturhist. Hofmus. Wien: 289

Merr. 1968: Fl. Manila: 67

Leach & Osborne 1985: Freshw. Pl. Papua New Guinea: 226

Hagstr. 1916 – In: Kungl. Svenska Vetenskapsakad. Handl.: 248

Hook.f. 1894 – In: Fl. Brit. India: 567

Cuong & Vidal 1983 – In: Fl. Camb., Laos & Vietnam: 58

Graebn. 1907 – In: Engl., Pflanzenr. 31: 83